TY - JOUR
T1 - Quantitative evaluation of α- and β-adrenoceptor modulation of [3H]choline release in guinea pig superior cervical ganglia
AU - Belluzzi, O.
AU - Travagli, R. A.
AU - Bonifazzi, C.
AU - Perri, V.
PY - 1987/1/2
Y1 - 1987/1/2
N2 - [3H] Overflow evoked by 5 min supramaximal preganglionic stimulation at 1 pps has been studied in isolated guinea pig superior cervical ganglion preparations preincubated with [3H]choline. At 15 μM norepinephrine (NE) reduced both the [3H]choline overflow and endogenous acetylcholine release by 59.4 and 54.1% respectively; the dose-response curve for NE inhibitory action is described. Evidence is given that endogenous catecholamines effectively reduce ACh release from the ganglia. After blocking the inhibitory action of endogenous NE, a significant β-adrenoceptor-mediated facilitatory effect on ACh release could be observed. Preincubation of the ganglia with different combinations of α1 and α2 agonists (phenylephrine, 10 μM and clonidine, 1 μM respectively) and antagonists (prazosin, 10 μM and yohimbine, 3 μM) showed that the adrenoceptors involved in α-mediated NE inhibition of ACh output are exclusively of the α2-type.
AB - [3H] Overflow evoked by 5 min supramaximal preganglionic stimulation at 1 pps has been studied in isolated guinea pig superior cervical ganglion preparations preincubated with [3H]choline. At 15 μM norepinephrine (NE) reduced both the [3H]choline overflow and endogenous acetylcholine release by 59.4 and 54.1% respectively; the dose-response curve for NE inhibitory action is described. Evidence is given that endogenous catecholamines effectively reduce ACh release from the ganglia. After blocking the inhibitory action of endogenous NE, a significant β-adrenoceptor-mediated facilitatory effect on ACh release could be observed. Preincubation of the ganglia with different combinations of α1 and α2 agonists (phenylephrine, 10 μM and clonidine, 1 μM respectively) and antagonists (prazosin, 10 μM and yohimbine, 3 μM) showed that the adrenoceptors involved in α-mediated NE inhibition of ACh output are exclusively of the α2-type.
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U2 - 10.1016/0304-3940(87)90032-2
DO - 10.1016/0304-3940(87)90032-2
M3 - Article
C2 - 3031550
AN - SCOPUS:0023206075
VL - 73
SP - 65
EP - 70
JO - Neuroscience Letters
JF - Neuroscience Letters
SN - 0304-3940
IS - 1
ER -